Ciencias Exactas y Ciencias de la Salud
Permanent URI for this collectionhttps://hdl.handle.net/11285/551039
Pertenecen a esta colección Tesis y Trabajos de grado de las Maestrías correspondientes a las Escuelas de Ingeniería y Ciencias así como a Medicina y Ciencias de la Salud.
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- Study of the mechanical behavior and cell viability on 3D-printed Ti6Al4V surfaces: porosity optimization for intervertebral spacer design(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2025-12) Hidalgo Ayala, Gabriela; García López, Erika; Lopez Botello, Omar Eduardo; mtyahinojosa, emipsanchez; Vázquez Lepe, Elisa Virginia; Trujillo de Santiago, Grissel; Escuela de Ingenieria y Ciencias; Campus MonterreyAdditively manufactured porous titanium implants offer a promising strategy to reduce stress shielding and promote bone interaction in spinal fusion procedures. In this work, Ti-6Al-4V lattice structures fabricated by Electron Beam Melting (EBM) were evaluated as candidates for intervertebral spacer applications. Three pore sizes (0.8 , 0.9, and 1.0 mm) were designed and produced using an Additive Arcam SPECTRA L (GE, Gothenburg, Sweden), along with solid EBM and cast Ti-6Al-4V controls. The study combined structural, mechanical, and in vitro biological characterization to determine how pore size influences performance. Dimensional analysis using scanning electron microscopy and ImageJ confirmed good geometric fidelity between CAD models and as-built lattices, with the 0.9 mm configuration showing the smallest deviation in pore diameter and strut thickness. Under uniaxial compression (ASTM E9), increasing pore size reduced both strength and stiffness. The 0.9 mm lattice exhibited a maximum compressive stress of approximately 564 MPa and an apparent modulus of approximately 13.5 GPa, values closer to those of vertebral trabecular bone than to those of solid Ti-6Al-4V. Attempts to perform compression fatigue testing (ASTM E466) revealed limitations of standard displacement-based preload protocols for highly compliant lattices, highlighting the need for adapted fatigue methodologies. A separate rotational fatigue test on a solid EBM specimen confirmed the correct functioning of the fatigue equipment. Biological performance was assessed using C2C12 murine myoblasts cultured on Ti-6Al-4V discs representing each pore size. Fluorescence imaging (Phalloidin/DAPI) showed robust cell adhesion and organized cytoskeletal structures across all lattices, while Live/Dead assays demonstrated high viability (>97%) with no pore size dependent cytotoxicity. Integrating mechanical, structural, and cellular findings, the 0.9 mm lattice emerged as the promising design, offering favorable balance between biomechanical compatibility, structural integrity and early cell response for potential use in intervertebral spacer implants.
- PVA /alginate/AgNPs/curcumin electrospun nanofibers-based nonwoven mat as wound dressing(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2025-06-13) Rodríguez Lee, Fernando Arturo; García López, Erika; emipsanchez; Rodríguez González, Ciro Ángel; Tejeda Alejandre, Raquel; School of Engineering and Sciences; Campus Monterrey; Vázquez Lepe, Elisa VirginiaWound healing requires advanced solutions that can support tissue regeneration, reduce inflammation, and prevent infections. This thesis presents the development of an electrospun wound dressing made from polyvinyl alcohol (PVA), alginate, silver nanoparticles (AgNPs), and curcumin. The objective was to create a multifunctional dressing capable of improving healing in burn wounds by combining the mechanical stability of PVA, the moisture retention of alginate, and the antimicrobial and anti-inflammatory properties of AgNPs and curcumin. Rheological tests were performed to identify critical polymer concentrations and determine the influence of molecular weight on fiber morphology. Electrospinning conditions were optimized to obtain bead-free nanofibers with diameters ranging from 200 to 600 nm. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) confirmed the presence and distribution of active agents in the fibers. Biological evaluation using fibroblast 3T3 cells under direct contact conditions demonstrated good cell compatibility, especially in the first three days. It is important to highlight that by day seven, the culture medium was not replaced, yet cells still showed metabolic activity despite the reduced nutrients and suboptimal pH. This result suggests that the material provides a suitable environment that supports cell viability over time. The results show that this electrospun dressing has potential for use in burn wound healing applications.
- Customizing a Cardiac Simulator Using 3D Printed Anatomic Models(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2024-12-03) Franco Ávila, Mónica Paola; García López, Erika; emimmayorquin; Tejeda Alejandre, Raquel; Segura Ibarra, Víctor; School of Engineering and Sciences; Campus Monterrey; Vázquez Lepe, Elisa VirginiaCardiac surgery relies on preparation from the interventionist cardiologists and other practitioners involved in order to avoid vascular complications after the operation for the patient. There have been studies performed alongside medical residents, which found that the number of cases needed to gain proficiency in cardiac procedures involving a catheter is at least 52. However, limited opportunities for practice before the catheterization result in fewer procedures being performed. Interventionist cardiologists can avoid the hazards of cadaveric dissection by using 3D printed anatomical models in conjunction with a flow simulator. The anatomical models can also help to highlight qualities that are not immediately visible in situ. These anatomical models can be customizable to the patient’s anatomy, thus minimizing the vascular complications rate and providing a sufficient learning curve to assure an optimal experience for all parties involved. Whilst creating the anatomical models for acardiac surgery simulator to perform TAVR, an idea emerged to adapt the heart model to allow the incorporation of medical devices through modularization and the adequacy through design for additive manufacturing of each section to work within the proposedsystem. The acquisition and reconstruction of the anatomical models was performed using segmentation and design software for medical images. The models then entered a production phase through additive manufacturing, using materials resembling the mechanical properties of organic tissue. These properties were tested to figure out anyresemblance with the values reported for the aorta. Afterwards, the manufactured models underwent a digitalization and inspection phase to verify their compliance against the original models. The anatomical models designed considered the trajectory interventionist cardiologists must go over to perform main types of cardiac catheterizations, along with the blood flow required to operate within the system of the simulator. In conclusion, the modularity of cardiac anatomic models and their use on a surgery simulator was achieved and could open the possibility for more practice spaces for medical professionals
- Influence of process parameters on surface integrity and topography of nitinol stents manufactured by fiber laser micro-cutting(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2023-12-07) Palencia Mercado, Giovanni; García López, Erika; mtyahinojosa, emipsanhez; Vázquez Lepe, Elisa Virginia; Rodríguez González, Ciro Ángel; School of Engineering and Sciencies; Campus Monterrey; Cedeño Viveros, Luis DanielNitinol alloys are commonly used for the manufacture of self-expanding stents. These materials have super-elasticity and shape memory properties, allowing better navigability and placement of the stent. Aortic valve implants have three manufactured parts to be considered: the support mesh (i.e., stent), a cover, and leaflets. This work explains the laser cutting procedure and the parameter variation for the stent manufacture, as well as the postprocessing techniques of electropolish and shape setting. A preliminary study was conducted to analyze the influence of the process parameters (spot overlap and pulse energy) on the dross, surface roughness, kerf width, and chemical composition. These outcomes have an effect on the stent surface integrity, which is related to microcracks and residual stresses, which negatively affect the stent performance. Our results indicated that dross surface percentage decreased with lower pulse energy (30.82 mJ) and higher spot overlap (83.31%), suggesting a relationship between these parameters. Results showed a reduction in the kerf width using lower pulse energy levels (i.e., 30.82 mJ, 31.49 mJ). Ra and Rz's surface roughness parameters were reduced with the highest pulse energy (32.16 mJ). According to the results, no consistent relationship was found between the spot overlap and the responses of the chemical composition and kerf width. Laser-cut samples presented a recast layer showing an increase in the Oxygen concentration reduction of the Nickel and Titanium, as well as an increase in the microhardness of the affected zone. It was found that these indicators are more prominent in certain zones where the cutting direction did not allow a proper ejection of the molten material, suggesting a relationship between the cutting direction and surface integrity for the proposed setup. The electropolish process achieved proper results to reduce Ra from 2.19 μm to 1.13 μm and from 1.3 μm to 0.91 μm, however, for samples with lower initial roughness it was not possible to reduce the response. For the shape setting treatment, best parameters (550 °C and 12 min) achieved an expansion of the stent with a small recoil of 0.8 mm.
- 3D printed emitters for nanofibers production using VAT photopolymerization(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2023-06-16) Almanza Vázquez, Luis Enrique; García López, Erika; dnbsrp; Rodríguez Gónzalez, Ciro Ángel; School of Engineering and Science; Campus Monterrey; Tejeda Alejandre, RaquelElectrospinning is a method centered on electrostatic forces for fabricating continuous nanofibers with a substantial active surface area per mass unit in which the morphology of electro spun nanofiber is influenced by some parameters such as voltage, space electric field distribution, surface charge density, liquid supply rate, solution surface tension, viscosity, conductivity, and humidity. This technique is being applied by designing a Multiplexed Source using VAT photopolymerization which will allow to produce the nanofibers. Several test probes varying geometrically (Hexagonal, Pentagonal, Quadrangular, Triangular and Circular) were designed to analyze the resolution of the EnvisionTEC and to observe if the multiplexed source geometry nozzles should be changed or remain the same. After an Error Data Analysis, it was concluded that the circular geometry was the one to work with because it does not get clogged by the time the experiments were computed thus because it does not have any angle or angles that affects its manufacturing in comparison with the other geometries. In this study the polymer used to produce the nanofibers was polyethylene oxide (PEO) with a molecular wight of 900,000 gr/mol. The electrospinning experiments were conducted at flow rates ranging from 0.1 and 1 ml / hr and working distances between 12.5 and 16.5 cm. The voltage remains constant at the value of 20kV. The collected fibers were analyzed using Scanning Electron Microscopy (SEM). Based on the solution and processing conditions, different structures from droplets, and heavily beaded fibers to defect-free mats were obtained. PEO’s concentration was 4% w/v and the volume of Deionized water was 96 ml. The solution was diluted and prepared by using a water bath for 8 hours until the PEO is completely diluted. Based on the solution and processing conditions, different structures from droplets, and heavily beaded fibers to defect-free mats were obtained and measured their diameter (if applicable) by using the image j software and by computing a Data analysis of the average diameter per sample of nanofibers check out which one is the optimal combination of parameters by producing the nanofibers. The final application of this is the manufacture of a multilayer patch for a biomedical application that is the tissue regeneration for second degree burning wounds.
- Feasibility study of micromilling for AISI 316L microneedles arrays(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2020-11-30) Tamez Tamez, Jeanette Itzel; García López, Erika; dnbsrp; School of Engineering and Sciences; Campus MonterreyMicroneedles market is expected to grow and the study of micromilling capabilities to meet medical requirements represents an opportunity of vast applications on this area. It is suggested that the limitations of this manufacturing process may lead to affect geometrical features of importance for insertion compliance. A study of the impact of the final geometric and surface features of the micromachined product on its functionality is necessary to fully understand this manufacturing technique in the medical area, especially the microdevices market. In this work, micromilling process with aid of Minimum Quantity Lubrication (MQL) system was used to manufacture AISI 316L square pyramidal (i.e., base length and height of 0.5 mm by 0.5 mm) microneedles arrays, and analysis of precision and reproducibility of measurements of height, base length, tip radius, tip angle, roughness and tool wear of ball nose micro end milling tool were performed. Based on the used cutting parameters, an optimal quantity of 30 microneedles can be manufactured to obtain values closed to those of design and guarantee insertion in skin. Simulations presented maximum radius tips of 50 microns to accomplish piercing
- Micro machinability of net shapes of Selective Laser Melting of Ti-6Al-4V for minimum material removal using ball end mill(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2018-05-15) Celis Renata, Pavel; Vázquez Lepe, Elisa Virginia; García López, Erika; Rodríguez González, Ciro Ángel; Sandoval Robles, Jesús A.Miniaturization of medical devices is playing an important role in the manufacture industry. New drug delivery systems are being studied and developed, therefore materials to produce these devices must be investigated extensively. The objective of this work is to experimentally investigate and compare the machinability of Ti-6Al-4V titanium alloy produced via Selective laser melting (SLM) against the conventional machining method. 18 patches of 09 needles each were fabricated and machined with different cutting feeds (120,150 and 180mm/min) with aid of a minimum quantity lubrication (MQL) system. Machinability was examined in terms of cutting forces, tool wear, surface roughness and geometrical dimensions. Each cutting feed was tested by fabricating 3 patches from solid blocks of titanium with square tools of .8mm. Finish pass was performed with a .2mm micro ball end mill with a constant spiral toolpath. Comparison was performed by fabricating four patches with SLM with an excess material of 150μm and machined with the same previous parameters. 3D images obtained by optical microscope reveal that the main force applied in the finishing of needles is the Z axis and cutting forces were higher when machining SLM patches. Tool calibration is the main factor to obtain high precision in geometrical dimensions due to the variation in length because of thermal expansion. Surface roughness for all tests were below 1μm with best results when cutting feed is set at 120mm/min, reduction in edge radius for ball end mills affected negatively the surface roughness. An economic comparison was performed and showed that the SLM combined with SM process has clear advantage over subtractive manufacture alone.